Terminals with multiple reception antennas can relatively easily mitigate intercell interference using time/space diversity in a downlink of an OFDMA system. However, in a terminal with a single reception antenna, intercell interference cancellation is a difficult task. The intercell interference greatly deteriorates mobility and stability of a mobile communication system in a cell boundary area.
Early technologies for intercell interference cancellation, which employ a single reception antenna in a downlink, were associated with Time Division Multiple Access (TDMA). According to TDMA, intracell interference can be avoided, but intercell interference exists in a cell boundary area to greatly deteriorate the system performance.
As a method for mitigating such intercell interference, a Maximum Likelihood Sequence Detection (MLSD) technique has been used to process, by joint detection, signals of several cells in a cell boundary area. However, since this technique uses a Viterbi algorithm for joint detection, it has a disadvantage in that the complexity increases exponentially with respect to the number of total users of all cells.
As a solution to such a computational complexity problem, an iterative reception technique based on the turbo principle has been proposed.
Further, another iterative reception technique based on Minimum Mean Squared Error (MMSE) MultiUser Detection (MUD) has been proposed for canceling intercell interference in a multicarrier Code Division Multiple Access (CDMA) system based on OFDMA technology. However, this technology also suffers from the problem of complexity in that an inverse of a matrix whose dimension is equal to the number (e.g., 1024) of multicarriers or arbitrary spreading elements should be calculated for every symbol.